1. Field of the Invention
The present invention relates to a vehicular air conditioning apparatus mounted in a vehicle for blowing air into a vehicle compartment that has been adjusted in temperature by a cooling means or a heating means, for thereby performing control of temperature in the vehicle compartment.
2. Description of the Related Art
In a vehicular air conditioning apparatus that is mounted in a vehicle, internal and external air is introduced into a casing by a blower, and after cooled air, which has been cooled by an evaporator that forms a cooling means, and heated air, which has been heated by a heater core that forms a heating means, are mixed together in the casing at a predetermined mixing ratio, the mixed air is blown out from a defroster blow-out port, a face blow-out port, or a foot blow-out port, whereby adjustment of temperature and humidity in the vehicle compartment is carried out.
With this type of vehicular air conditioning apparatus, for example, it is known to provide a first blower for the purpose of introducing vehicle compartment air into the casing, and a second blower for the purpose of introducing internal and external air outside of the vehicle compartment into the casing. In such a vehicular air conditioning apparatus, air that is introduced from an internal air introduction port by rotation of the first blower is heated by a first heat exchanger and then is blown into the vehicle compartment through a first air passage from the face blow-out port or the foot blow-out port. In addition, air that is introduced from an external air introduction port by rotation of the second blower is heated by a second heat exchanger and then is blown into the vehicle compartment through a second air passage from the defroster blow-out port. More specifically, a switching operation is performed such that when air is blown out from the face blow-out port or the foot blow-out port, the first blower is driven and air from the interior of the vehicle is introduced, whereas when air is blown out from the defroster blow-out port, the second blower is rotated and external air is introduced.
Further, using separate air conditioning devices having first and second blowers for introducing air, the first blower is arranged facing toward an external air introducing port of a duct, and the second blower is arranged facing toward an interior air introducing port. Additionally, the first blower includes a switching means, which is capable of switching the air that is introduced to the duct by the first blower between interior air and exterior air.
In addition, the air that is introduced to the duct by the first blower is switched between interior air and exterior air by the switching means, and after the air has been adjusted in temperature by a heating means and a cooling means so as to provide a desired temperature together with the air introduced to the duct by the second blower, the air is blown into a desired region in the vehicle compartment through a face blow-out port, a foot blow-out port, or a defroster blow-out port. (See, for example, Japanese Laid-Open Patent Publication No. 05-178068, Japanese Laid-Open Patent Publication No. 06-040236, and Japanese Laid-Open Patent Publication No. 06-191257.)
However, in this type of vehicular air conditioning apparatus having two first and second blowers, in the case that one of the first and second blowers is halted, air which is supplied from the one blower that is being driven tends to flow through to the side of the other blower while passing through the interior of the first and second heat exchangers, and to be blown into the vehicle compartment. More specifically, inside the vehicle compartment, blowing of air occurs unintentionally from the blow-out port for which blowing of air has been stopped, thereby imparting a sense of discomfort to occupants in the vehicle.